National Repository of Grey Literature 60 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
The deposition of CaF2 ultrathin layers on graphene substrate
Caesar, Radek ; Nebojsa, Alois (referee) ; Mach, Jindřich (advisor)
This master’s thesis is focused on preparation and analysis of ultrathin CaF2 (calcium fluoride) films on a graphene substrate. CaF2 was deposited in UHV conditions at substrate temperatures in the range from 20 °C to 400 °C. The material was deposited on Si(111) with a native SiO2 layer and on a substrate with a CVD graphene layer. The deposited films were analyzed by XPS, AFM and SEM. Moreover four different sample holders for deposition purposes were designed in this work.
Design of manipulator for TEM
Melichárek, Václav ; Doležel, Pavel (referee) ; Mach, Jindřich (advisor)
The topic of this master’s thesis is the design of a sample manipulator for TEM. Regarding which the segment of the sample manipulator used to move the sample in the direction of the x-axis (so-called x-stage) was designed. The introductory theoretical part is concerned with a brief description of transmission electron microscopy focused on the imaging methods used in TEM and the procedures of preparing and loading TEM samples. The theoretical part follows with the design of precise mechanisms, especially with respect to the inaccuracies of their operation and the technological aspect of the design. In the practical part, a detailed analysis of the design of the x-stage is presented. Kinematics and dynamics of the mechanism is analyzed in depth, following with the description of the overall design of the mechanism and some of its parts in detail.
Design of adjusment mechanism of Wehnelt cylinder of electron gun
Franc, Viktor ; Mach, Jindřich (referee) ; Zlámal, Jakub (advisor)
One of the essential elements of thermionic electron gun is Wehnelt cylinder and it’s adjustment mechanism. This bachelor thesis is dedicated to the design of the mechanism. There are also described different types of electron guns and their function.
Preparation of graphene membranes for Ga deposition
Severa, Jiří ; Bartošík, Miroslav (referee) ; Mach, Jindřich (advisor)
This bachelor’s thesis deals with the production of graphene membranes, which would be suitable for the deposition of gallium atoms. In the first part is characterized graphene. The second part is focused on preparation and improvement the production of graphene layers via atomically flat Cu foils. In the third part are described graphene membranes, techniques of their production and specific applications of graphene membranes. The fourth part introduced interface between gallium and graphene layers. The fifth part is the practical part. Graphene was grown on different Cu foils which resulted in higher quality graphene grown on smooth foils. Subsequently, the production of graphene membranes and deposition of gallium atoms were done.
Optimization of devices for deposition GaN nanostructures
Šimek, Daniel ; Voborný, Stanislav (referee) ; Mach, Jindřich (advisor)
This bachelor thesis deals with the automation of sources for the deposition of GaN nanocrystals used at the Institute of Physical Engineering. For the purpose of the thesis, the mechanism of automatic control of the gallium effusion cell shutter was designed and constructed and the control electronics containing components enabling automatic switching of the ion atomic source of nitrogen ions. In addition, samples of GaN nanocrystals on four different substrates that were studied for cold electron emission were prepared by the method of ion beam assisted molecular beam epitaxy IBA-MBE. The results of the measurement are discussed in the conclusion.
Optimization of Carbon atomic source for graphene layer growth by MBE method
Liška, Petr ; Bartošík, Miroslav (referee) ; Mach, Jindřich (advisor)
This bachelor’s thesis deals with the development and optimization of an atomic source of carbon atoms with the thermal energy (0.1÷1 eV). An atomic beam in the conditions of ultrahigh vacuum is considered to be a suitable source of superior graphene layers also due to the high purity of the method. The first part of this work describes graphene as a material and the method of molecular beam epitaxy. The second part is dedicated to the description of an assembly of the carbon source and its optimization which also concludes with experimental data obtained from measurement of the deposited carbon layers on various substrates (Cu, Ge, Al2O3, SiO2).
Deposition of GaN nanocrystals with Ga droplets
Novák, Jakub ; Voborný, Stanislav (referee) ; Mach, Jindřich (advisor)
This bachelor thesis deals with preparation and characterization of Ga structures and GaN nanocrystals. In the theoretical part, properties and applications of GaN are introduced. Further, some substrates for the growth and some techniques used for manufacturing of these structures are stated. Further, is also mentioned the photoluminiscence of GaN. The experimental part deals with preparation of Ga and GaN structures and combination of both. These structures were further analyzed by various methods such as XPS, SEM or photoluminiscence.
Optimization of thermal dissociation atomic hydrogen source for use SEM
Melichárek, Václav ; Polčák, Josef (referee) ; Mach, Jindřich (advisor)
The focus of this bachelor's thesis is the optimization of a thermal dissociation monoatomic hydrogen source. The project entailed the design and construction of a new control electronics for the thermal dissociation source, because the source has been powered using universal laboratory power supplies until now. The thesis begins with a brief introduction into the interaction of graphene with monoatomic hydrogen, the operational principle and construction of the monoatomic hydrogen source. Furthermore, the requirements on the design of the electronics are specified. A more detailed analysis of possible solutions, and the selection of the optimal solution were also conducted. The practical part discusses the conceptual designs in detail and describes the selection of the optimal solution. It follows by elaborating on the implementation of the control electronics in detail, its design and construction, and the electrical circuit in particular.
Schottky solar cells with interface graphene/si modified by GaN
Mohelský, Ivan ; Voborný, Stanislav (referee) ; Mach, Jindřich (advisor)
This bachelor thesis deals with fabrication and characterization of Schottky solar cells with graphene/silicon junction. For this study, the I-V characteristic measuring device was designed and assembled. Also, the graphene/silicon junction was modified by GaN nanocrystals and properties of such a solar cell was studied.
Design of manipulator for ultrahigh electron microscope
Caesar, Radek ; Mach, Jindřich (referee) ; Bábor, Petr (advisor)
The main purpose of this thesis is mechanical design of a manipulator for an ultra-high vacuum scanning electron microscope (UHV SEM), being currently developed by TESCAN ORSAY HOLDING a.s. in cooperation with the Institute of physical engineering FME BUT. The manipulator is supposed to be able to handle with specimens in so-called preparation chamber, which the specimens are put in before placing into the analytic chamber. In the preparation chamber the surface finishing and also other operations are made. In the theoretical part some of the technologies used in vacuum engineering, especially various principles of pressure measurement and gas pumping, are described. Besides, the thesis is focused on a brief description of UHV SEM being developed and the methods of specimen preparation. The practical part deals with the concept and the mechanical design of manipulator itself.

National Repository of Grey Literature : 60 records found   1 - 10nextend  jump to record:
See also: similar author names
16 MACH, Jan
14 MACH, Jiří
4 Mach, Jakub
16 Mach, Jan
14 Mach, Jiří
2 Mach, Jonáš
Interested in being notified about new results for this query?
Subscribe to the RSS feed.